• Journal of Microbiology and Biotechnology
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• v.15 no.3
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• pp.519-524
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• 2005

An ${\alpha}$-L-rhamnosidase (EC 3.2.1.40.), which transforms quercitrin to quercetin, was purified from Fusobacterium K-60, a human intestinal anaerobic bacterium. The specific activity of the purified ${\alpha}$-L-rhamnosidase was 2.89 mol/min/mg protein. ${\alpha}$-L-Rhamnosidase, whose molecular size was 170 kDa by gel filtration, was composed of four subunits ($M_r$ 41,000 Da) with pI and optimal pH values of 5.2 and 5.5-7.0, respectively. The apparent $K_m$ and $V_{max}$ values for p-nitrophenyl-${\alpha}$-L-rhamnopyranoside and quercitrin were determined to be 0.057 mM and 3.4 mol/min/mg, and 0.077 mM and 5.0 mol/min/mg, respectively. This enzyme was strongly inhibited by $Cu^{2+},\;Mn^{2+}$, L-rhamnose, and p-chlormercuriphenylsulfonic acid. These findings suggest that the biochemical properties and substrate specificity of the purified enzyme are different from those of the previously purified ${\alpha}$-L-rhamnosidase. This is the first reported purification of quercitrin-hydrolyzing ${\alpha}$-L-rhamnosidase from intestinal bacteria.

• Microbiology and Biotechnology Letters
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• v.45 no.4
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• pp.305-310
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• 2017

Twelve lactic acid bacteria harboring ${\alpha}$-rhamnosidase (EC 3.2.1.40) activity were isolated from traditional Korean foods. The 6 strains (Weissella confuse [n = 1], Lactobacillus pentosus [n = 1], and Lactobacillus plantarum [n = 4]) with the highest rhamnosidase activity were selected for bioconversion of an extract of wood-cultivated ginseng. The L. plantarum MBE/L2990 strain increased ginsenoside content (0.58 mg for Rg1 and 0.24 mg for Rg5) and showed higher bioconversion activity than the control strain L. plantarum KCTC21004 (56% and 42% increase for Rg1 and Rg5, respectively). L. plantarum MBE/L2990 was deposited at the Korean Collection for Type Cultures as Lactobacillus plantarum KCTC18529P.

• Proceedings of the PSK Conference
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• 2000.04a
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• pp.154.2-154.2
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• 2000

• Journal of Microbiology and Biotechnology
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• v.31 no.3
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• pp.419-428
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• 2021

To efficiently recycle GH78 thermostable rhamnosidase (TpeRha) and easily separate it from the reaction mixture and furtherly improve the enzyme properties, the magnetic particle Fe3O4-SiO2-NH2-Cellu-ZIF8 (FSNcZ8) was prepared by modifying Fe3O4-NH2 with tetraethyl silicate (TEOS), microcrystalline cellulose and zinc nitrate hexahydrate. FSNcZ8 displayed better magnetic stability and higher-temperature stability than unmodified Fe3O4-NH2 (FN), and it was used to adsorb and immobilize TpeRha from Thermotoga petrophilea 13995. As for properties, FSNcZ8-TpeRha showed optimal reaction temperature and pH of 90℃ and 5.0, while its highest activity approached 714 U/g. In addition, FSNcZ8-TpeRha had better higher-temperature stability than FN. After incubation at 80℃ for 3 h, the residual enzyme activities of FSNcZ8-TpeRha, FN-TpeRha and free enzyme were 93.5%, 63.32%, and 62.77%, respectively. The organic solvent tolerance and the monosaccharides tolerance of FSNcZ8-TpeRha, compared with free TpeRha, were greatly improved. Using naringin (1 mmol/l) as the substrate, the optimal conversion conditions were as follows: FSNcZ8-TpeRha concentration was 6 U/ml; induction temperature was 80℃; the pH was 5.5; induction time was 30 min, and the yield of products was the same as free enzyme. After repeating the reaction 10 times, the conversion of naringin remained above 80%, showing great improvement of the catalytic efficiency and repeated utilization of the immobilized α-L-rhamnosidase.

• Journal of Microbiology and Biotechnology
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• v.33 no.11
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• pp.1521-1530
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• 2023

An α-L-rhamnosidase gene from Thermoclostridium. stercorarium subsp. thermolacticum DSM 2910 (TstRhaA) was cloned and expressed. The maximum TstRhaA activity of the protein reached 25.2 U/ml, and the molecular mass was approximately 106.6 kDa. The protein was purified 8.0-fold by Ni-TED affinity with an overall recovery of 16.6% and a specific activity of 187.9 U/mg. TstRhaA activity was the highest at 65℃ and pH 6.5. In addition, it exhibited excellent thermal stability, better pH stability, good tolerance to low concentrations of organic reagents, and high catalytic activity for p-nitrophenyl-α-L-rhamnopyranoside (pNPR). Substrate specificity studies showed that TstRhaA exhibited a high specific activity for rutin. At 60℃, pH 6.5, and 0.3 U/ml enzyme dosage, 60 g/l rutin was converted to 45.55 g/l isoquercitrin within 150 min. The molar conversion rate of rutin and the yield of isoquercitrin were 99.8% and 12.22 g/l/h, respectively. The results suggested that TstRhaA could be used for mass production of isoquercitrin.

• Journal of Ginseng Research
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• v.24 no.2
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• pp.89-93
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• 2000

WB were screening the stele and the cortex of the ginseng roots (Panax ginseng C.A.Meyer) on the exo-0-glycosylhydrolase activities during vegetation period of 1999 year. The following p-nitrophenylglycosides were used to test exe-0-glycosylhydrolase activities: $\alpha$- and $\beta$-D-galactopyranosides,$\alpha$- and $\beta$-D-glucopyranosides, $\alpha$- and $\beta$-D-mannopyranosides, N-acetyl-$\beta$-D-glucosaminide, $\alpha$- and $\beta$-D-xylopyranosides $\alpha$- L-rhamnopyranoside, $\beta$-D-glucuronide, $\beta$-D-galacturonide, $\beta$-L-,$\alpha$-L- and $\beta$-D-fucopyranosides, $\alpha$-L-arabinopyranoside. Only $\beta$-D-galactosidase, $\alpha$-L-mannosi-dase , N- acetyl- ${\beta}$-D-slucosarninidase, $\alpha$-D-galacto sidase, $\alpha$-L-arabinosidase, and $\beta$-D-fuco sidase were found in both partsof ginseng roots. Their contents during the vegetation period were shown to differ considerably, being dependent not only on plant development stage but on plant tissue and environmental conditions too.

• Food Science and Biotechnology
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• v.18 no.6
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• pp.1365-1370
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• 2009

Aspergillus kawachii extracellular pectinases were screened in liquid cultures with different carbon sources. The fungus grown on citrus pectin or lemon pomace produced at least one of these inducible pectinases: acidic polygalacturonase, pectin lyase, pectin methylesterase, $\alpha$-L-arabinofuranosidase, $\alpha$-1,5-endoarabinase, $\beta$-D-galactosidase/exogalactanase, and $\beta$-1,4-endogalactanase. The lemon-pomace filtrates also contained significant $\alpha$-L-rhamnosidase and $\beta$-D-fucosidase activities. Most of the screened pectinases were active at pH 2.0-2.5, indicating that the A. kawachii enzymes were acidophilic. Under the culture conditions employed we could not detect enzymatic degradation of soybean rhamnogalacturonan. The A. kawachii pectinase-production-related regulatory phenomena of induction-repression resemble those described for other Aspergillus sp.

• YAKHAK HOEJI
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• v.40 no.3
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• pp.335-339
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• 1996

Optimal medium for growth and glycosidases production of Bacteroides JY-6, an human intestinal bacterium, was general anaerobic medium or tryptic soy broth containing sod ium thioglycolate and ascorbic acid. By cocultivation of Staphylococcus R-48, Bacteroides JY-6 could be cultured in LB broth unable to culture JY-6. Heated Staphylococcus R-48 was also the inducer of the production of Bacteroides JY-6 glycosidases. These glycosidases were induced well by natural flavonoid glycosides, such as poncirin, naringin and rutin, but were not by synthetic substrates, p-nitrophenyl ${\beta$-D-glucopyranoside and p-nitrophenyl ${\alpha}$-L-rhanmopyranoside.

• Journal of Microbiology and Biotechnology
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• v.16 no.10
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• pp.1613-1621
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• 2006

Isolation and identification of algal lytic bacteria were carried out. Nine strains of algal lytic bacteria were isolated by the double-layer method using Anabaena flos-aquae as a sole nutrient. The isolate, AFK-13, showing the highest algal lytic activity was identified as Sinorhizobium kostiense based on the l6S rDNA sequence. The algal lytic experiments of the culture supernatants of AFK-13 demonstrated that the bacterial cell growth reached a maximum at 36-h culture, but the supernatant of 72-h culture exhibited the highest activity. Components among the extracellular products in the crude enzyme of the supernatant from S. kostiense AFK-13 culture were responsible for degradation of cell walls of Anabaena flos-aquae. Algal lytic assay tests of the culture supernatants suggest that the main substances for algal lytic activity could be proteinaceous. The activity of glucosidase was observed highly by polysaccharolytic analysis using the crude enzyme from S. kostiense AFK-13, whereas activities of galactosidase, mannosidase, rhamnosidase, and arabinosidase were also detected in low levels. The molecular weights (MW) of ${\alpha}-\;and\;{\beta}$-glucosidases were estimated to be approximately 50-100 kDa by the ultrafiltration method.